Comparison of defects in ProTaper hand-operated and engine-driven instruments after clinical use

AIM

To compare the type of defects and mode of material failure of engine-driven and hand-operated ProTaper instruments after clinical use.

METHODOLOGY

A total of 401 hand-operated and 325 engine-driven ProTaper instruments were discarded from an endodontic clinic over 17 months. Those that had fractured were examined for plastic deformation in lateral view and remounted for fractographical examination in scanning electron microscope. The mode of fracture was classified as 'fatigue' or 'shear' failure. The lengths of fractured segments in both instruments were recorded. Any distortion in hand instrument was noted. Data were analysed using chi-square, Fisher's exact or Student's t-test, where appropriate.

RESULTS

Approximately 14% of all discarded hand-operated instruments and 14% of engine-driven instruments were fractured. About 62% of hand instruments failed because of shear fracture, compared with approximately 66% of engine-driven instruments as a result of fatigue (P < 0.05). Approximately 16% of hand instruments were affected by shear, and either remained intact or was fractured, compared with 5% of engine-driven instruments (P < 0.05). The length of the broken fragment was significantly shorter in hand versus engine-driven group (P < 0.05). Approximately 7% of hand instruments were discarded intact but distorted (rarely for engine-driven instruments); all were in the form of unscrewing of the flutes. The location of defects in hand Finishing instruments was significantly closer to the tip than that for Shaping instruments (P < 0.05).

CONCLUSIONS

Under the conditions of this study (possibly high usage), the failure mode of ProTaper engine-driven and hand-operated instruments appeared to be different, with shear failure being more prevalent in the latter.

Immunogenicity and persistence of a targeted anti-caries DNA vaccine

We have previously reported that a targeted anti-caries DNA vaccine, pGJA-P, induced accelerated and increased antibody responses compared with a non-targeted anti-caries DNA vaccine. Recently, pGJA-P/VAX, a new targeted anti-caries DNA vaccine for human trials, was constructed by replacing the pCI vector used in the construction of pGJA-P with pVAX1, the only vector authorized by the US Food and Drug Administration in clinical trials. Here, we report on our exploration of the kinetics of the antibody responses generated following pGJA-P/VAX immunization and the persistence of pGJA-P/VAX at both the inoculation site and the draining lymph nodes. Intranasal vaccination of mice with pGJA-P/VAX induced strong antibody responses that lasted for more than 6 months. Furthermore, pGJA-P/VAX could still be detected at both the inoculation site and the draining cervical lymph nodes 6 months after immunization. Thus, the persistent immune responses are likely due to the DNA depot in the host, which acts as a booster immunization.

Protective efficacy of a targeted anti-caries DNA plasmid against cariogenic bacteria infections

We have previously reported that a targeted anti-caries DNA plasmid pGJA-P/VAX which was constructed against the antigenic determinants of Streptococcus mutans (S. mutans) successfully induced antibody responses in mice and monkeys. The present study explored the protective efficacy of pGJA-P/VAX against cariogenic bacterial challenge. Groups of rats were orally challenged with S. mutans or Streptococcus sobrinus (S. sobrinus) and then immunized with pGJA-P/VAX or the vector pVAX1 intranasally. Serum IgG and salivary IgA antibody levels were assessed by an enzyme-linked immunosorbent assay and caries activity was evaluated by the Keyes method. The results showed that specific salivary IgA antibody responses were induced following intranasal vaccination with pGJA-P/VAX. Moreover, immunization with pGJA-P/VAX resulted in significantly reduced enamel and dentinal caries lesions in rats after S. mutans infection and significantly reduced enamel caries lesions after S. sobrinus infection. Thus, pGJA-P/VAX was not only protective toward S. mutans infection, but also provided cross-strain protection against S. sobrinus infection in rats.

The inhibitory effect of magnolol from Magnolia officinalis on glucosyltransferase

Dental caries has been an intractable disease in spite of intense dental research. Glucosyltransferase (GTF) enzyme plays the most important role in the development of dental caries. In our previous studies, magnolol, a compound from Magnolia officinalis Rehder et Wilson (Magnoliaceae), was shown to possess a strong anti-GTF activity. The purpose of the present study was to examine the effect of magnolol on the functional domains of GTF for the purpose of defining its anti-GTF activity mechanism. GTF-I which was prepared from Streptococcus milleri transformant KSB8 cells expressing the gtfB gene was used. The results demonstrated magnolol reduced total glucan synthesis, depending on the magnolol concentration. There were no significant differences in Michaelis constant (K(m)) values between the presence and absence of magnolol as determined by Lineweaver-Burk plot, and maximum velocity (V(m)) in the presence of magnolol was lower than that in its absence. Magnolol significantly inhibited both sucrose hydrolysis and glucosyl transfer to glucan by GTF-I. Free glucose in the presence of magnolol was reduced by 33-48% as compared to in its absence, while the quantity of glucan was reduced by 75-82%. These findings suggested that magnolol inhibited both two sequential reaction phases of GTF non-competitively by operating on the glucan-binding domain, but not on the catalytic domain. Magnolol could be a valuable resource for the exploration of novel bioactive compounds in natural products.

A two-year randomized clinical trial of chlorhexidine varnish on dental caries in Chinese preschool children

The objective of this study was to assess the effect of six-monthly professional applications of chlorhexidine varnish on the prevention of dental caries in primary molars in Chinese preschool children. In a double-blinded, randomized, placebo-controlled clinical trial, 334 children aged 4-5 years were randomly divided into two groups. Children in the test group received six-monthly applications of a 40% chlorhexidine varnish, and the control children received a placebo varnish. Caries status of the children was assessed by two calibrated examiners at baseline and after 24 months, according to criteria recommended by the World Health Organization. The two-year mean caries increments in the test and the control group children were 1.0 and 1.6 decayed, missing, or filled molar surfaces (dmfs-molar), respectively, a 37.3% reduction (t test, p = 0.036). No side-effects were found. It was concluded that six-monthly applications of chlorhexidine varnish were effective in reducing the incidence of dental caries in primary molars.

Evaluation of the accuracy of three electronic apex locators using glass tubules

AIM

To evaluate the accuracy of three different electronic apex locators (EALs) using glass tubules.

METHODOLOGY

Forty-eight glass tubules with different diameters and an agar model were used to mimic root canals. A size 15 stainless steel K-file was used as the measuring electrode. The Root ZX, Propex and Neosono Ultima EZ were used to measure the tubule length with tubules dry, or filled with 0.9% NaCl, 3% H(2)O(2), 2.5% NaOCl or 17% EDTA. The distance between the real length (RL) and measured length (ML) of the tubules was recorded. The range of RL +/- 0.5 mm and RL +/- 1 mm was used to evaluate the accuracy of the EALs. Results were subject to correlation analysis and Friedman's test.

RESULTS

In dry tubules, the accuracy of Root ZX was 75-91.7% for RL +/- 0.5 mm and 100% for RL +/- 1 mm, whilst the measurements of the other two EALs were all within the RL +/- 0.5 mm. No influence from the increase in tubule diameter on the accuracy of all three EALs was observed in dry tubules. In tubules filled with electrolyte, the accuracy of the Root ZX decreased as tubule diameter increased (R(d) > 0, P < 0.05). The RL-ML distance recorded by Propex was inversely related to the tubule diameter (R(d) < 0, P < 0.05). The accuracy of Propex was 75-100% for RL +/- 0.5 mm and 100% for RL +/- 0.5 mm when the tubule diameter was not more than 0.80 mm, but decreased in tubules with diameter over 0.80 mm and filled with 2.5% NaOCl or 17% EDTA. Nearly, all the measurements (except for six tubules) using Neosono Ultima EZ were within 1 mm shorter than RL despite the contents in tubules and the increase of tubule diameter.

CONCLUSIONS

The accuracy of the Root ZX decreased as the tubule diameter increased when tubules were filled with electrolytes. The electrolytes in the tubules decreased the accuracy of Propex when the tubule diameter was large. The electrolytes in tubules and tubule diameter had no influence on the accuracy of Neosono Ultima EZ. The Propex and Neosono Ultima EZ were more accurate than the Root ZX under various conditions in this laboratory study.

The aggressive form of cherubism: report of two cases in unrelated families

Cherubism is a benign lesion that causes painless symmetrical enlargement of the jaws, usually with a familial tendency. We describe in two Chinese families two cases of the aggressive form of cherubism with extensive swelling on both sides of the mandible, typical microscopic findings, and apparent familial history.

Defects in ProTaper S1 instruments after clinical use: fractographic examination

AIM

To investigate the mode of failure of a brand of nickel-titanium instruments separated during clinical use, by detailed examination of the fracture surface.

METHODOLOGY

A total of 122 ProTaper S1 instruments were discarded from an endodontic clinic at a stomatological school in China over a period of 17 months; 28 had fractured. These fractured instruments were ultrasonically cleaned, autoclaved and then examined under a scanning electron microscope. From the lateral view the fracture was classified into 'torsional' or 'flexural'. The specimens were then re-mounted and the presence of characteristics of shear failure and fatigue striations was recorded under high-power view of the fracture surface. The difference in the mean lengths of fractured segment between the shear and fatigue groups was compared using Student's t-test.

RESULTS

Twenty-seven separated instruments were available for analysis. Under low-power magnification, only two fell into the category of 'torsional' failure when examined laterally; the others appeared to be 'flexural'. Close examination of the fracture surface revealed the presence of fatigue striations in 18 specimens. Nine instruments (including the two putative 'torsional' failures above) fell into the shear fracture group, in which fatigue striations were absent or characteristics of shear failure of the material were found. The mean length of fractured segments resulting from fatigue failure (4.3+/-1.9 mm) was significantly greater than that for shear failure (2.5+/-0.8 mm) (P<0.001, two-sample t-test).

CONCLUSIONS

Examination of the fracture surface at high magnification is essential to reveal features that may indicate the possible origin of cracks and the mode of material failure. Macroscopic or lateral examination of separated instruments would fail to reveal the true mechanism of failure. Fatigue seems to be an important reason for the separation of rotary instruments during clinical use.

Differentiation ability of rat postnatal dental pulp cells in vitro

The current rapid progression in stem cell research has enhanced our knowledge of dental tissue regeneration. In this study, rat dental pulp cells were isolated and their differentiation ability was evaluated. First, dental pulp cells were obtained from maxillary incisors of male Wistar rats. Immunochemistry by stem cell marker STRO-1 proved the existence of stem cells or progenitors in the isolated cell population. The dissociated cells were then cultured both on smooth surfaces and on three-dimensional (3-D) scaffold materials in medium supplemented with beta-glycerophosphate, dexamethasone, and L-ascorbic acid. Cultures were analyzed by light and scanning electron microscopy and, on proliferation, alkaline phosphatase activity and calcium content were determined and the polymerase chain reaction was performed for dentin sialophosphoprotein, osteocalcin, and collagen type I. These cells showed the ability to differentiate into odontoblast-like cells and produced calcified nodules, which had components similar to dentin. In addition, we found that the "odontogenic" properties of the isolated cells were supported by three-dimensional calcium phosphate and titanium scaffolds equally well.

A novel locus for autosomal dominant hereditary gingival fibromatosis, GINGF3, maps to chromosome 2p22.3-p23.3

Hereditary gingival fibromatosis (HGF) is a rare, benign disorder characterized by slowly progressive fibrous overgrowth of the gingiva. To date, two loci have been mapped in familial cases with autosomal dominant non-syndromic HGF: GINGF (MIM 135300) on chromosome 2p21-p22 and GINGF2 (MIM 605544) on chromosome 5q13-q22. Of the two loci, only SOS1 (son of sevenless one, MIM 182530) gene underlying GINGF locus has been identified. Ascertainment of a large Chinese family has allowed the mapping of a novel locus to 2p22.3-p23.3, GINGF3. Haplotype construction and analysis localized the new locus to an 11.4-cM interval between markers D2S2221 (telomeric) and D2S1788 (centromeric). The maximum two-point limit of detection (LOD) score of 3.45 (theta=0) and multipoint LOD score of 5.00 for marker D2S390 strongly supported linkage to this region. Thus, this genetic interval is distal to and does not overlap with the previously described locus, GINGF, on 2p21-p22.

Clinical and radiological features of odontogenic ghost cell carcinoma: review of the literature and report of four new cases

OBJECTIVES

To analyse systematically the clinical and radiological features of odontogenic ghost cell carcinoma (OGCC).

METHODS

Clinical and radiological features of 22 OGCCs (4 new and 18 from the literature) were analysed.

RESULTS

There were 17 (77%) males and 5 (23%) females (male-to-female ratio of 3.4:1). Ages ranged from 13 years to 72 years (mean 36.7) with a peak in the fourth (40.9%) and fifth (27.3%) decades. The maxilla was involved in 68% and the mandible in 32%. Our study confirmed that OGCC is more prevalent in Asians (12/18) than in other racial groups. The mixed radiolucent and radiopaque lesion pattern was the most frequent (14/19) compared with radiolucent lesions (5/19). 89% (17/19) showed poorly defined borders and 11% (2/19) showed well defined borders. Root resorption was reported in 31% (6/19) of patients and tooth displacements in 21%.

CONCLUSIONS

OGCC demonstrates clinical and radiographic features of a malignant tumour with high recurrence.

Construction and immunogenic characterization of a fusion anti-caries DNA vaccine against PAc and glucosyltransferase I of Streptococcus mutans

Glucosyltransferases (GTFs) and A cell-surface protein (PAc) are two important virulence factors of the cariogenic organism Streptococcus mutans. They may mediate sucrose-independent or sucrose-dependent attachment of Streptococcus mutans to tooth surfaces, respectively. Thus, inhibiting both virulence factors is predicted to provide better protection against caries than inhibiting a single factor. To develop a highly efficient vaccine against caries, we constructed a fusion DNA vaccine, pGLUA-P, by cloning the GLU region of GTF into a DNA vaccine, pCIA-P, which encodes two highly conservative regions of PAc. In this report, we provide evidence that fewer caries lesions were observed in rats following subcutaneous injection of pGLUA-P, compared with pCIA-P, near the submandibular gland. Our findings suggest that a multigenic DNA vaccine may be more caries-preventive than a single-gene DNA vaccine.

A comparison of instrument-centering ability within the root canal for three contemporary instrumentation techniques

AIM

To study and compare Great Taper (GT) hand files using a reversed balanced force technique, nickel-titanium (NiTi)flex files with a balanced force technique and stainless steel (SS) K-type files using a step-back technique.

METHODOLOGY

Forty-eight extracted mandibular premolar teeth with single root canals having curvatures between 15 and 45 degrees were prepared using a modified Bramante model and randomly divided into three groups. The teeth were cross-sectioned at 2, 6 and 10 mm from the working length. Preoperative images of canals at three levels were captured at 20x magnification using a stereomicroscope. Canals in each group were, respectively, prepared to an apical size.10 GT file with 0.2 mm tip diameter, size 30 NiTiflex file and size 30 SS K-file. The GT file was used in a reversed balanced force technique, the NiTiflex file was used in a balanced force technique, and the SS K-file was used in a step-back technique. Postoperative canals were imaged under the conditions same as those for the preoperative canals. The postoperative images were superimposed over the preoperative images using software photoshop 6.0. The ability to maintain the instrument in the central axis of the canal and the deviation from the central canal axis were determined and compared by statistical analysis, along with the assessment of the amount of dentine removed.

RESULTS

At apical level, the centering ratio, the distance of transportation and the dentine removed in GT and NiTiflex groups were significantly less than those in SS group (P < 0.01), but no statistical differences were found between the two NiTi groups. At other levels, there were no substantial differences amongst the groups.

CONCLUSIONS

Compared with SS K-files, GT hand files and NiTiflex files remain better centered and produce significantly less transportation in curved canals.

Expression of Plasmodium falciparum-infected erythrocyte membrane protein from cerebral malaria patients

AIM

To provide theoretical evidence for studying the molecular pathogenesis of human cerebral malaria.

METHODS

The expressions of Plasmodium falciparum erythrocyte membrane protein 1(PfEMP1) on the surface of parasitized erythrocyte (PE) specimens from 19 cases of cerebral malaria patients in Yunnan Province were quantitatively analyzed by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) technique. 43 patients of falciparum malaria, 9 patients of vivax malaria and 6 healthy controls were also investigated.

RESULTS

The expressions of higher molecular mass (Mr) 260-320 kDa forms of PfEMP1 were found on PE from cerebral malaria patients. By contrast, the expression of PfEMP1 and P. vivax erythrocyte membrane protein (PvEMP1) on PE from falciparum malaria patients and vivax malaria patients had a PfEMP1 with Mr 240 kDa and a PvEMP1 with Mr 180 kDa band, respectively. Healthy controls expressed an EMP of Mr 140 kDa.

CONCLUSION

The binding of 260-320 kDa PfEMP1 proteins expressed on PE from cerebral malaria patients to diverse receptor molecules on the endothelial cell(EC) of the cerebral microvessels such as CD36, thrombospondin (TSP), intercellular adhesion molecule 1(ICAM-1), vascular cell adhesion molecule 1(VCAM-1), endothelial leukocyte adhesion molecule 1(ELAM-1) and chondroitin sulfate A (CSA) might be the molecular basis for the pathogenesis of cerebral malaria.

A DNA vaccine encoding a cell-surface protein antigen of Streptococcus mutans protects gnotobiotic rats from caries

A cell-surface protein antigen (PAc) of Streptococcus mutans is considered a virulence factor because it may mediate initial attachment of Streptococcus mutans to tooth surfaces. Thus, inhibiting PAc is predicted to provide protection against caries. To develop vaccines against dental caries, we constructed a DNA vaccine, pCIA-P, which encodes two high-conservative regions of PAc. Expression of the recombinant protein was obtained in eukaryotic cells in vitro and in vivo. In this report, we provide evidence that fewer caries lesions, and high levels of PAc-specific salivary IgA antibody and serum IgG antibody, were observed in gnotobiotic rats following targeted salivary gland (TSG) administration of pCIA-P. This study shows that the recombinant DNA vaccine pCIA-P could induce protective anti-caries immune responses and that TSG immunization is a promising strategy for the inhibition of dental caries.

[Experimental study of bacteriostatic activity of Chinese herbal medicines on primary cariogenic bacteria in vitro]

OBJECTIVE

To screen some Chinese herbal medicines for their inhibitory activity on cariogenic bacteria, and investigate their active ingredients, and measure their minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC).

METHODS

Active components were isolated from every tested Chinese herbal medicine by means of aqueous extraction and ethanolic extraction. Berberine was purified from Coptis chinensis Fra. Disk agar diffusion method was employed in screening herbs with inhibiting effect on cariogenic bacteria. MIC and MBC were determined by broth dilution method.

RESULTS

Against Streptococcus mutans Ingbritt, MBCs of Magnolia officinalis ethanolic extract, Berberine, Coptis chinensis Fra aqueous extract and Coptis chinensis Fra ethanolic extract were 0.488, 0.625, 7.800 and 1.950 g/L respectively. Against Streptococcus sobrinus 6715, MBCs of Magnolia extract, Coptis chinensis Fra ethanolic extract, Rhus chinensis Mill ethanolic extract and Phellodendron chinen ethanolic extract were 0.488, 0.625, 1.950, 3.900, 3.900 and 3.900 g/L respectively. Against Actinomyces viscosus ATCC 19246, MBCs of Berberine, Coptis chinensis Fra aqueous extract, Coptis chinensis Fra ethanolic extract, Rheum palmatum L aqueous extract and Rheum palmatum L ethanolic extract were 1.250, 3.900, 3.900, 15.600 and 31.250 g/L respectively.

CONCLUSIONS

Magnolia officinalis, Coptis chinensis Fran, Rheum palmatum L aqueous extracts exhibit strong inhibition on cariogenic bacteria. Magnolia officinalis ethanolic extract has the strongest bactericidal effects on Streptococcus mutans and Streptococcus sobrinus.

Caries experience and oral health behavior in Chinese children with cleft lip and/or palate

PURPOSE

The aims of this study were to investigate whether there were different caries levels in 3- to 6-year-old Chinese children who had a cleft lip compared to those with a cleft lip/palate. The goal also was to evaluate parental attitudes toward the feeding habits and oral health care for their children.

METHODS

A cross-sectional study was carried out through a dental examination of a sample of children and a questionnaire to their parents. A sample of 104 3- to 6-year-old children (66 boys and 38 girls) with cleft lip, cleft palate or both were selected from those receiving pre-surgical treatment. Each child was examined and a short questionnaire was given to parents of the children. The form included questions about infant feeding practices, frequency consumption of specific drinks and, children's toothbrushing frequency.

RESULTS

One hundred and four children were examined. Seventy-five percent had some caries experience and rampant caries was present in 26%. Children with cleft palate had a higher prevalence of rampant caries (30%) compared to those with cleft lip (12%). A multivariate analysis yielded feeding practices and mother's education as the variables significantly associated with caries and rampant caries.

CONCLUSIONS

The results of this study show that: 1. Children with a cleft lip/palate have higher levels of dental caries compared to those with a cleft lip alone; 2. The two most important factors for dental caries were: a. whether the child had been bottle-fed and; b. the educational attainment level of the mother.

[Immunolocalization of laminin during reparative dentinogenesis]

OBJECTIVE

To investigate the immunolocalization of laminin in the process of dental pulp injury and repair.

METHODS

One cavity was prepared on the mesial surface of the first molars of Wistar rats. The animals were sacrificed in 3, 15, and 30 days of post-operation. After histological process, the paraffin sections were reacted with monoclonal antibodies against rat laminin using SABC method.

RESULTS

Immunolocalization demonstrated positive staining for laminin in the different stages of dental pulp repair. In 3 days group, no reparative dentin were observed. The positive staining was located in odontoblasts and in predentin. After 15 days, reparative dentin and odontoblasts were observed. The odontoblast like cells and dental pulp cells were stained positively. 30 days later, the stronger staining intensity was observed in odontoblast like cells, pulp cells and in reparative dentin. Immunological reaction was particularly located among the interface of reparative dentin and dental pulp.

CONCLUSION

The localization feature of laminin suggested that laminin may be a favored factor for the adhesion of dental pulp cell during reparative dentinogenesis.

Selective estrogen receptor modulators and coronary heart disease

The vasculature has been recognized as an important target of estrogen action through rapid non-genomic effects and/or via the classic pathway (genomic effects) involving estrogen receptors (ER-alpha and ER-beta). Multiple mechanisms participate in the regulation of different estrogen-controlled genes, providing a wide spectrum of possibilities for development of drugs, including pure agonists or antagonists or mixed agonists/antagonists, the so-called selective estrogen receptor modulators (SERM). In theory, an ideal SERM should reduce the risks of coronary heart disease (CHD) and preserve bone density, without or with very low incidences of breast and endometrial neoplasms or venous thromboembolism (VTE). The precise mechanism for the protective effects of estrogens and their receptors on cardiovascular diseases is not yet fully established. In this review, we summarize the recent advances in understanding the action of ERs/ligands, the therapeutic implications for CHD, and highlight the recent progress of both clinical and basic studies on the protection issue. Finally, a number of newly developed SERMs and their clinical applications as well as the laboratory investigations are discussed.

Experiences from a school-based oral health promotion programme in Wuhan City, PR China

OBJECTIVES

To evaluate the effect of a six-year oral health promotion programme for school children of Wuhan City, PR China.

METHODS

The programme group (P-group) comprised 233 children who had just entered grade 1 (1989). The programme provided an oral health promotion programme, and 215 12-year-old children from three schools participated as a control group (C-group). After the 6-year period of the programme (1995), all of the children had a clinical examination according to the criteria of the WHO and responded to a structured questionnaire on dental health behaviour.

RESULTS

The results showed that attitudes to dental care, regular tooth brushing habits, use of fluoridated toothpaste, gingival health and dental visits, frequencies of consuming sugary drinks/foods were improved in the p-group when compared with the C-group.

CONCLUSION

The school-based oral health promotion programme should be expanded.

[Clinical study on effects of root canal instrumentation on the root canal microflora]

OBJECTIVE

To investigate the effects of instrumentation and ultrasonic treatment on the root canal flora.

METHODS

A total of 21 single-rooted teeth with chronic apical periodontitis were selected and prepared using step-back/ultrasonic technique, Samples were taken before and after the step-back preparation, and after the ultrasonic treatment.

RESULTS

The number and species of bacteria in the root canal were both reduced dramatically and there were significant differences among the three groups (P < 0.05).

CONCLUSION

The instrumentation and ultrasonic treatment of root canal can effectively reduce the number and species of root canal microflora.

[Effects of immune bovine whey on sucrose-dependent adherence of Streptococcus mutans]

OBJECTIVE

The aim of this experiment is to explore the possible anti-carious mechanisms of immune bovine whey.

METHODS

The immune milk was collected from cows immunized with cell associated glucosyltransferase(GFT) over-expression strain B-29-33 of Streptococcus mutans(S. mutans) MT8148. The control milk was obtained from non-immunized cows. The immune and control bovine whey were prepared by removing fat and casein. The effects of two kinds of bovine whey on sucrose-dependent adherence of S. mutans MT8148 were examined by using TTY media with five different volumes of the immune and the control milk, 100, 300, 500, 700 and 900 microliters respectively. The adherent rates were determined by reading the optical density. The adherent morphology was observed by using a scanning electron microscope(SEM).

RESULTS

There was no significant difference in adherence of S. mutans MT8148 cells to the smooth glass surface among five doses with those of the control whey. The immune bovine whey inhibited the adherence of S. mutans. The adherent percentage was 84.37% at 100 microliters and decreased by 58.59% at 900 microliters. The inhibition was does-dependent. The difference of adherent morphology between the immune and control whey was noticeable at 900 microliters. The SEM revealed that cells of S. mutans MT8148 with the control whey were covered by large quantities of gelatinous material, but cells with the immune whey were clearly distinguished.

CONCLUSION

The immune whey has inhibitory potential against the sucrose-dependent adherence of S. mutans.